Method for selection of high M6P recombinant proteins

A method for producing purified recombinant human acid alpha-glucosidase (rhGAA), wherein the purified rhGAA comprises an amino acid sequence that is at least 98% identical to SEQ ID NO:

• 2, the method comprising:
• i) in a bioreactor, culturing host cells that secrete the rhGAA;
• ii) removing medium from the bioreactor;
• iii) filtering the medium to provide a filtrate;
• iv) loading the filtrate onto a first chromatography column to capture the rhGAA, wherein the first chromatography column is an anion exchange chromatography (AEX) column, wherein the filtrate is not loaded onto a chromatography column prior to the AEX column;
• and
• v) eluting the rhGAA from the AEX column,
• wherein the purified rhGAA comprises at least 3.0% of the total N-glycans of the rhGAA are in the form of a bis-mannose-6-phosphate (bis-M6P) N-glycan and wherein at least 90% of the purified rhGAA binds to cation-independent mannose-6-phosphate receptor (CIMPR).